194 



whom Mr. Ball has in many instances received valuable aid 

 in zoological pursuits. The fins of both these species of Ros- 

 siae are like in form and position to those of Sepiola Ronde- 

 letii. 



16. Spirula australis. Shell found at Yougbal, 1820. 



IliefoUoimng are the Measurements of the Rossics in Inches : 



Bossia Rossia 



Owenii. Jacobii. 



Length of body, l? . . 2-1 



Breadth over fins, 2-0 . . 2*7 



Length of fin, 0-7 . . \5 



Extreme breadth, 0-45 . . 0*7 



Breadth between eyes, 0*9 . . \'2 



Extreme breadth of head, 1*1 . . 1*4 



Length of head, 0-5 . . 0-7 



Length of tentaculae, 4-0 . . 5*7 



Portion of tentaculae occupied by Aceta- 



bula, 0-9 . . 1-5 



Length of first pair of arms, counting 



from top of head, S'l . . 2'2 



Ditto, second ditto, ditto, 2'4 . . 2*3 



Ditto, third ditto, ditto, 2*7 . . 2*6 



Ditto, fourth ditto, ditto, 2-3 . . 2-4 



Depth of fin between first pair of arms, 0*2 . , 0*4 



Ditto, first and second do. 0'3 • . 0*5 



Ditto, second and third do. 0-42 . . 0-6 



Ditto, third and fourth do. 0-4 . . 0-8 



Ditto, fourth do. 0-04 . . 0-03 



William Roberts, Esq., F.T. CD., read a paper on a class 

 of spherical curves, the arcs of which represent the three 

 species of elliptic transcendents. 



A cone of the second order, whose vertex is upon the 

 surface of a sphere, and one of whose principal axes is a 

 diameter, will intersect the sphere along a curve which ad- 



